US5329451A - Steerable trailer and steering apparatus of combination vehicle - Google Patents

Steerable trailer and steering apparatus of combination vehicle Download PDF

Info

Publication number
US5329451A
US5329451A US08/073,500 US7350093A US5329451A US 5329451 A US5329451 A US 5329451A US 7350093 A US7350093 A US 7350093A US 5329451 A US5329451 A US 5329451A
Authority
US
United States
Prior art keywords
trailer
tractor
steering angle
wheel steering
coupling
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US08/073,500
Inventor
Ikurou Notsu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
UD Trucks Corp
Original Assignee
UD Trucks Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP1990099741U external-priority patent/JP2515731Y2/en
Priority claimed from JP1990107914U external-priority patent/JP2542574Y2/en
Application filed by UD Trucks Corp filed Critical UD Trucks Corp
Priority to US08/073,500 priority Critical patent/US5329451A/en
Application granted granted Critical
Publication of US5329451A publication Critical patent/US5329451A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B62LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62DMOTOR VEHICLES; TRAILERS
    • B62D7/00Steering linkage; Stub axles or their mountings
    • B62D7/06Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins
    • B62D7/14Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering
    • B62D7/142Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering specially adapted for particular vehicles, e.g. tractors, carts, earth-moving vehicles, trucks
    • B62D7/144Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering specially adapted for particular vehicles, e.g. tractors, carts, earth-moving vehicles, trucks for vehicles with more than two axles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B62LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62DMOTOR VEHICLES; TRAILERS
    • B62D13/00Steering specially adapted for trailers
    • B62D13/04Steering specially adapted for trailers for individually-pivoted wheels
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B62LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62DMOTOR VEHICLES; TRAILERS
    • B62D7/00Steering linkage; Stub axles or their mountings
    • B62D7/06Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins
    • B62D7/14Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering
    • B62D7/15Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering characterised by means varying the ratio between the steering angles of the steered wheels
    • B62D7/159Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering characterised by means varying the ratio between the steering angles of the steered wheels characterised by computing methods or stabilisation processes or systems, e.g. responding to yaw rate, lateral wind, load, road condition

Definitions

  • the present invention relates to a semi-trailer with all wheels steerable.
  • the present invention relates to a steering apparatus of a combination vehicle, that is, a semi-trailer.
  • a steerable trailer As regards a steerable trailer, a full trailer is shown in the official gazette Japanese Patent Application Disclosure No. 61-60379. Also, a prior art of a semi-trailer is shown in the official gazette Japanese Patent Application Disclosure No. 56-163968. In the latter prior art, a steering mechanism of trailer wheels is controlled in response to output signals from a feedback circuit provided in a control circuit including a microcomputer which receives electric signals representing a steering status of the front wheel and a rotational status of the wheel as input signals. Also, in the latter art, a path of the trailer may approach that of the tractor so that a tractor and trailer can pass through a narrow curved path, and can prevent any obstacle from being caught under the wheels with the least inward turning.
  • a steering apparatus of a combination vehicle a steering apparatus of a full trailer is shown in the above-mentioned official gazette Japanese Patent Application Disclosure No. 61-60379. Also, a steering apparatus of a semi-trailer is shown in Japanese Utility Model Application No. 1-20202, which has been filed with the Japanese Patent Office in the name of the applicant.
  • Another object of the present invention is to provide a steerable trailer due to a simple control and no restrictions on the tractor for a trailer to be coupled.
  • the present invention provides a combination vehicle comprising:
  • front wheel steering angle detecting means for detecting a front wheel steering angle
  • coupling angle detecting means for detecting a coupling angle
  • rear wheel steering angle detecting means for detecting a rear wheel steering angle
  • trailer wheel steering angle detecting means for detecting a trailer wheel steering angle
  • control means for calculating and memorizing a travel direction of a front end of the tractor at voluntary points in response to signals transmitted from each of said detecting means, said control means transmitting output signals to each of said actuators so as to align travel directions of a coupling point and a rear end of the trailer with the memorized direction when the coupling point and the rear of the trailer reach a voluntary point.
  • the coupling angle detection means comprises a coupling angle sensor being attached to a coupler and detecting a relative angle between center lines of the tractor and trailer.
  • control means comprises a controller including a microcomputer.
  • the controller calculates a travel direction on the front end of the tractor due to the front wheel steering angle being detected and memorizes the direction.
  • the controller calculates a rear wheel steering angle such that a travel direction of the coupling point (referred to as point B) is equal to the travel direction on the front end of the tractor when point B reaches a location of the point A, and then, the controller controls the rear wheel actuator.
  • the controller calculates a trailer wheel steering angle such that a travel direction of the rear end (referred to as point C) of the trailer is equal to the above-mentioned travel direction when point C reaches a location of the point A, and then, the controller controls the trailer wheel actuator.
  • a steerable trailer comprising:
  • a controller for controlling the steering mechanism so that a rear end of the trailer may follow (and/or trace) a path of a coupling point.
  • a side slip angle should be considered in order to determine a travel direction of the coupling point.
  • the sideslip angle can be considered as zero. Therefore, the controller can control the rear end of a trailer so as to make the rear end of the trailer follow (and/or trace) a path of the coupling point, due to a simple operation control calculation.
  • FIG. 1 is a general arrangement showing an embodiment of the present invention.
  • FIG. 2 is a control block diagram.
  • FIG. 3 is a control flow chart.
  • FIG. 4 is a drawing for explaining a unit distance.
  • FIG. 5 is a drawing for explaining a calculation mode.
  • FIG. 6 is a general arrangement showing an embodiment of the present invention.
  • FIGS. 7 and 8 are plans for explaining the calculation modes.
  • FIG. 9 is a control flow chart while the key switch is ON.
  • FIG. 10 is a control flow chart of detection and storage of coupling angle.
  • FIG. 11 is a control flow chart for calculating the rear wheel target steering angle.
  • a steering mechanism 2 for steering a front wheel of a tractor T which includes a front wheel steering angle sensor 3 as a front wheel steering angle detection means.
  • a rear wheel 4 a rear wheel hydraulic cylinder 5 and rear wheel steering angle sensor 7 is provided as a rear wheel steering angle detection means.
  • a tractor T is provided with a vehicle speed sensor 8.
  • the sensor 10 is provided as a coupling angle detection means.
  • Trailer wheel 11 is provided with a trailer wheel hydraulic cylinder 12 and a trailer wheel steering angle sensor 16 as a trailer wheel steering angle detection means.
  • Actuators 5 and 12 are selectively connected with a hydraulic pump 14 or an oil tank 15 through servo valves 6 and 13, respectively. Also, sensors 3, 7, 8, 10, and 16, and servo valves 6 and 13 are connected with controller 20 individually.
  • a controller 20 which comprises a circuit including a microcomputer, is provided with a central processing unit (CPU) 21.
  • CPU 21 central processing unit
  • the CPU 21 is connected with the front wheel steering angle sensor 3, vehicle speed sensor 8, and coupling angle sensor 10.
  • signals from these sensors 3, 8, and 10 are input to CPU 21 through the input interface 24.
  • output interface 25 being followed by D/A conventers 26 and 28, a signal from CPU 21 is transmitted to a rear wheel servo amplifier 27 and a trailer wheel servo amplifier 29, respectively.
  • controller 20 is provided with ROM 22 for memorizing programs and operation expressions, and RAM 23 for memorizing a travel direction of the front end of the tractor at a voluntary point, which direction is calculated by CPU 21.
  • the above rear wheel servo amplifier 27 is connected with the rear wheel hydraulic cylinder 5, and also, the amplifier 27 is directly connected with rear wheel steering angle sensor 7.
  • a trailer wheel servo amplifier 29 is connected with the trailer wheel hydraulic cylinder 12, and also, the amplifier 29 is directly connected with the trailer wheel steering angle sensor 16.
  • controller 20 Upon controlling, as shown in FIG. 3, with every travel of a prescribed unit distance D (shown in FIG. 4) being calculated due to signals from vehicle speed sensor 8 (step S1 is YES), controller 20 detects the front wheel steering angle and coupling angle (steps S2 and S3) due to signals from front wheel steering angle sensor 3 and coupling angle sensor 10. Then, the controller 20 calculates the rear wheel steering angle, trailer wheel steering angle, tractor yawing angle, and trailer yawing angle (steps S4, S5, S6, and S7). Next, the controller 20 calculates a travel direction of front end of the tractor T at a voluntary point (step 8). Due to this calculated result, controller 20 outputs control signals to the rear wheel hydraulic cylinder 5 and trailer wheel hydraulic cylinder 12, and then, controlling procedure returns to step S1.
  • symbols A, B, C, and P denote a point of the front end of the tractor T, coupling point, point of the rear end of trailer R, and a center of gravity of wheel base L of tractor T, respectively.
  • symbols ⁇ f, ⁇ r, and ⁇ t denote steering angles of the front wheel 1, rear wheel 4, and trailer wheel 11, respectively. Additionally, all of the angles are represented by radian.
  • Sh(i) corresponds to a direction in which the coupling point B should be advanced.
  • a rear wheel steering angle ⁇ r with which angle the coupling point B may advance in the direction of Sh(i), is:
  • Angle of sideslip ⁇ B 1 of coupling point B, which angle ⁇ B 1 is viewed from trailer R, is:
  • a sideslip angle ⁇ C of point C on the rear end is:
  • Sh(1) corresponds to a direction in which point C should be advanced.
  • a trailer wheel steering angle ⁇ t with which the point C can advance in the direction of the yawing angle Sh(1) is:
  • Vehicle angle in a unit time that is, yawing angle ⁇ 1 is:
  • the controller calculates Sh(n), which represents a travel direction of point A, due to the front wheel steering angle ⁇ f, and memorizes Sh(n) in RAM 23. Also, the controller calculates the rear wheel steering angle ⁇ r so that the coupling point B may advance in the same direction, that is, the travel direction on the front end of the tractor when point B reaches a location of the point A. And then, the controller controls the rear wheel hydraulic actuator 5.
  • the controller calculates the trailer wheel steering angle so that point C may advance in the same direction, that is, the travel direction on the front end of the tractor when point C reaches a location of the point A. And then, the controller controls trailer wheel hydraulic actuator 12.
  • a tractor 101 is provided with a steering 111 and link mechanism 113 for steering a pair of front wheels 112 in combination with the steering 111. Also, the tractor 101 is provided with a front wheel steering angle sensor 114 for detecting a steered angle of front wheel 112 by measuring an angle of steering 111, and a coupling angle sensor 117 which is attached to a coupler 116 and detects a coupling angle of the coupler 116. And a numeral 118 denotes a pair of rear wheel of the tractor 101.
  • the trailer 102 is provided with a vehicle speed sensor 115 for outputting a pulse signal, a frequency of which signal is proportional to a number of revolutions of the rear wheel, link mechanism 122 for steering the rear wheel 121, and a hydraulic actuator 123 for driving the link mechanism 122.
  • the actuator 123 is connected with an oil pump 124 and an oil tank 125.
  • These members 122-126 construct the steering mechanism.
  • the trailer 102 is provided with a rear wheel steering angle sensor 127 for detecting a steering angle of rear wheel 121.
  • These members, 114, 115, 117, 126 and 127 are connected with a controller, respectively.
  • the controller is represented by a numeral 131, in general.
  • the controller 131 consists of a microcomputer.
  • a CPU 134 in the controller 131 is connected with a A/D converter 132, which is connected with the front wheel steering angle sensor 114 and the coupling angle sensor 117, and a pulse input interface 133 which is connected with vehicle speed sensor 115.
  • ROM 136 and RAM 137 are connected with the CPU 134, respectively.
  • the CPU 134 is connected with the servo valve 126, and the servo amplifier 135 is connected with the rear wheel steering angle sensor 127.
  • C.G. center of gravity of the trailer 102.
  • a yawing rate ⁇ 1 is:
  • a sideslip angle ⁇ 1 of center of gravity C.G. is:
  • a sideslip angle ⁇ c of point C is:
  • equation (3) is:
  • a character Lh denotes a distance between the rear wheel set of tractor 101 and the coupling point H
  • a sideslip angle ⁇ h being viewed from the coupling point, that is, point H, is:
  • a character L denotes a wheel base of the tractor 101. Since the distance Lh is so small as compared with the wheel base L, a value of "Lh/L" can be neglected, and therefore, we get:
  • a travel direction ⁇ h of point H is:
  • a yawing angle ⁇ 1 (x) is represented as follows:
  • Equation (9) may also be transformed as follows:
  • the controller operates and/or calculates a travel direction of the point H with every unit travel distance ⁇ x by the equation (5), and memorizes the travel direction in RAM 137. And then, the controller controls a target steering angle of rear wheel 121 of the trailer 102 by the equation (11), so as to make the point C move and/or pass in the same travel direction with the travel direction of the point H memorized in RAM 137 when the point C comes to a location that the point H has already passed.
  • step S1 the controller 131 resets the previously memorized yawing angle ⁇ 1 to zero (step S1), and then, sets a counter of unit travel distance ⁇ x to 1 (step S2).
  • step S3 the controller sets the travel direction ⁇ h(i) to zero (step S3), and increases a value of the count by one (step S4).
  • step S5 is YES
  • step S5 the controller returns.
  • a target travel direction of the point C is kept in initialized condition that the point C moves in a straight advance direction until the point C reaches a location where the point H has passed.
  • step S10 With every unit time ⁇ t, due to signals generated from the coupling angle sensor 117, the controller 131 detects the coupling angle ⁇ (step S10), eliminates noises (step S11), stores the coupling angle in RAM 137 (step S12), and returns.
  • the controller 131 reads the coupling angle ⁇ , the yawing angle ⁇ , the travel direction ⁇ h(1) of the point H at the time that the point H was at the present location of the point C, and items (weight and lengths Lc, Lfr, Ltf, Lt, etc.) of the trailer 102 (steps S20, S21, S22, and S23).
  • controller 131 calculates the target steering angle ⁇ t of the rear wheel 121 with reference to the equation (11) (step S24), and sets the count to 1 (step S25). Then, controller 131 increases the data value of the travel direction ⁇ h(i) by one (step S26), increases count value by one (step S27), and determines whether the count value has reached a predetermined count (value) n (step S28).
  • step S26 If No, the controller 131 returns to step S26.
  • the controller 131 calculates a travel direction of the point II by the equation (5) (step S29), stores such the direction in RAM 137 (step S30). Then, the controller 131 calculates the yawing rate ⁇ 1 by the equation (1) (step S31), calculates the yawing angle ⁇ 1 (x) by the equation (10) (step S32), outputs a signal of the target steering angle ⁇ t to the servo amplifier 135 (step S32), and then, returns.
  • the present invention constructed as explained above, is able to control steering angles of rear wheel and trailer wheels by a feed forward control, make paths of any point on the front end of tractor, coupling point, and a point on the rear end of trailer concur (align) with one another, reduce inner wheel difference of the trailer, make a turn without overhang problems, and improve mobility thereof.
  • the present invention is constructed as mentioned above, the rear wheel of trailer can be steered with a simple control, and the mobility of the vehicle carring out the present invention is improved.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Theoretical Computer Science (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)
  • Steering-Linkage Mechanisms And Four-Wheel Steering (AREA)

Abstract

A combination vehicle is described herein including a tractor and a trailer. A front wheel steering angle detector is included for detecting a front wheel steering angle. A coupling angle detector also is included for detecting a coupling angle of a coupling point between the tractor and trailer. The rear wheel steering angle and the trailer wheel steering angle are detected via a rear wheel steering angle detector and a trailer wheel steering angle detector, respectively. Actuators are included for steering the rear wheels and the trailer wheels separately. A controller is provided for calculating and memorizing a travel direction of a front end of the tractor at a location in response to signals transmitted from the detectors. The controller transmits output signals to the actuators so as to align travel directions of the coupling point and the rear end of the trailer with the memorized direction of the front end of the tractor when the coupling point and the rear end of trailer reach the location. The controller calculates and memorizes the travel direction of the front end of the tractor at plural, discrete locations and transmits output signals to the actuators so as to align the travel direction of the coupling point and the rear end of the trailer with the memorized direction of the front end of the tractor when the coupling point and the rear end of the trailer reach the discrete locations.

Description

This is a divisional of co-pending application Ser. No. 07/764,304 filed on Sep. 24, 1991, now U.S. Pat. No. 5,289,892, which application is entirely incorporated by reference.
FIELD
The present invention relates to a semi-trailer with all wheels steerable.
Also, the present invention relates to a steering apparatus of a combination vehicle, that is, a semi-trailer.
PRIOR ART
As regards a steerable trailer, a full trailer is shown in the official gazette Japanese Patent Application Disclosure No. 61-60379. Also, a prior art of a semi-trailer is shown in the official gazette Japanese Patent Application Disclosure No. 56-163968. In the latter prior art, a steering mechanism of trailer wheels is controlled in response to output signals from a feedback circuit provided in a control circuit including a microcomputer which receives electric signals representing a steering status of the front wheel and a rotational status of the wheel as input signals. Also, in the latter art, a path of the trailer may approach that of the tractor so that a tractor and trailer can pass through a narrow curved path, and can prevent any obstacle from being caught under the wheels with the least inward turning.
In the above-mentioned prior art, since steering thereof is controlled with a feedback control and rear wheels thereof are non-steering wheels, it is difficult to make a path of the trailer align with that of the tractor. Therefore, it gives a low mobility.
As regards a steering apparatus of a combination vehicle, a steering apparatus of a full trailer is shown in the above-mentioned official gazette Japanese Patent Application Disclosure No. 61-60379. Also, a steering apparatus of a semi-trailer is shown in Japanese Utility Model Application No. 1-20202, which has been filed with the Japanese Patent Office in the name of the applicant.
The above-mentioned prior art is effective in itself. However, since the rear wheel steering angle is controlled so as to make a rear end of trailer follow (and/or trace) a path of the front end of the tractor, a complicated operation is required to control the steering angle. Also, since trailer items (distances between coupler and rear end, coupler and rear wheel set, and rear wheel set and rear end) are included in the operation expression, there is a nonconformity by which the trailers to be coupled are restricted.
SUMMARY
It is an object of the present invention to provide a combination vehicle which makes all of the path of the front end of the tractor, coupling point, and rear end of the trailer concur (align) with one another so as to improve a mobility thereof.
Another object of the present invention is to provide a steerable trailer due to a simple control and no restrictions on the tractor for a trailer to be coupled.
The present invention provides a combination vehicle comprising:
front wheel steering angle detecting means for detecting a front wheel steering angle;
coupling angle detecting means for detecting a coupling angle;
rear wheel steering angle detecting means for detecting a rear wheel steering angle;
trailer wheel steering angle detecting means for detecting a trailer wheel steering angle;
actuators for steering the rear wheels of the tractor and trailer, separately; and
control means for calculating and memorizing a travel direction of a front end of the tractor at voluntary points in response to signals transmitted from each of said detecting means, said control means transmitting output signals to each of said actuators so as to align travel directions of a coupling point and a rear end of the trailer with the memorized direction when the coupling point and the rear of the trailer reach a voluntary point.
It is preferable that the coupling angle detection means comprises a coupling angle sensor being attached to a coupler and detecting a relative angle between center lines of the tractor and trailer.
Also, it is preferable that the control means comprises a controller including a microcomputer.
In the combination vehicle being constructed as mentioned-above, at a voluntary point (represented by a point A), the controller calculates a travel direction on the front end of the tractor due to the front wheel steering angle being detected and memorizes the direction. Next, the controller calculates a rear wheel steering angle such that a travel direction of the coupling point (referred to as point B) is equal to the travel direction on the front end of the tractor when point B reaches a location of the point A, and then, the controller controls the rear wheel actuator.
Also, the controller calculates a trailer wheel steering angle such that a travel direction of the rear end (referred to as point C) of the trailer is equal to the above-mentioned travel direction when point C reaches a location of the point A, and then, the controller controls the trailer wheel actuator.
By the above-mentioned manner, steering angles of rear and trailer wheels are predicted, the rear wheel actuator and the trailer wheel actuator are controlled, and then, all of the paths of points A, B, and C concur (align) with one another.
According to the present invention, it is provided a steerable trailer comprising:
a steering mechanism for steering rear wheels; and
a controller for controlling the steering mechanism so that a rear end of the trailer may follow (and/or trace) a path of a coupling point.
Originally, a side slip angle should be considered in order to determine a travel direction of the coupling point. However, since a distance between the rear wheel set of a tractor and the coupling point is short, the sideslip angle can be considered as zero. Therefore, the controller can control the rear end of a trailer so as to make the rear end of the trailer follow (and/or trace) a path of the coupling point, due to a simple operation control calculation.
Embodiments of the present invention are explained hereinafter with reference to the accompanied drawings.
FIG. 1 is a general arrangement showing an embodiment of the present invention.
FIG. 2 is a control block diagram.
FIG. 3 is a control flow chart.
FIG. 4 is a drawing for explaining a unit distance.
FIG. 5 is a drawing for explaining a calculation mode.
FIG. 6 is a general arrangement showing an embodiment of the present invention.
FIGS. 7 and 8 are plans for explaining the calculation modes.
FIG. 9 is a control flow chart while the key switch is ON.
FIG. 10 is a control flow chart of detection and storage of coupling angle.
FIG. 11 is a control flow chart for calculating the rear wheel target steering angle.
EMBODIMENT
The first embodiment of the present invention is explained with reference to FIGS. 1-5.
In FIG. 1, a steering mechanism 2 for steering a front wheel of a tractor T which includes a front wheel steering angle sensor 3 as a front wheel steering angle detection means. In a rear wheel 4, a rear wheel hydraulic cylinder 5 and rear wheel steering angle sensor 7 is provided as a rear wheel steering angle detection means. Also, a tractor T is provided with a vehicle speed sensor 8.
A coupler 9, which is a coupling point of tractor T and trailer R, is provided with a coupling angle sensor 10 for detecting a relative angle between center lines of tractor T and trailer R. The sensor 10 is provided as a coupling angle detection means.
Trailer wheel 11 is provided with a trailer wheel hydraulic cylinder 12 and a trailer wheel steering angle sensor 16 as a trailer wheel steering angle detection means. Actuators 5 and 12 are selectively connected with a hydraulic pump 14 or an oil tank 15 through servo valves 6 and 13, respectively. Also, sensors 3, 7, 8, 10, and 16, and servo valves 6 and 13 are connected with controller 20 individually.
In FIG. 2, a controller 20, which comprises a circuit including a microcomputer, is provided with a central processing unit (CPU) 21. Through an input interface 24, the CPU 21 is connected with the front wheel steering angle sensor 3, vehicle speed sensor 8, and coupling angle sensor 10. Thus, signals from these sensors 3, 8, and 10 are input to CPU 21 through the input interface 24. Also, through output interface 25 being followed by D/ A conventers 26 and 28, a signal from CPU 21 is transmitted to a rear wheel servo amplifier 27 and a trailer wheel servo amplifier 29, respectively. In addition to the CPU 21, controller 20 is provided with ROM 22 for memorizing programs and operation expressions, and RAM 23 for memorizing a travel direction of the front end of the tractor at a voluntary point, which direction is calculated by CPU 21. Through the servo valve 6, the above rear wheel servo amplifier 27 is connected with the rear wheel hydraulic cylinder 5, and also, the amplifier 27 is directly connected with rear wheel steering angle sensor 7. Similarly, through a servo valve 13, a trailer wheel servo amplifier 29 is connected with the trailer wheel hydraulic cylinder 12, and also, the amplifier 29 is directly connected with the trailer wheel steering angle sensor 16.
Upon controlling, as shown in FIG. 3, with every travel of a prescribed unit distance D (shown in FIG. 4) being calculated due to signals from vehicle speed sensor 8 (step S1 is YES), controller 20 detects the front wheel steering angle and coupling angle (steps S2 and S3) due to signals from front wheel steering angle sensor 3 and coupling angle sensor 10. Then, the controller 20 calculates the rear wheel steering angle, trailer wheel steering angle, tractor yawing angle, and trailer yawing angle (steps S4, S5, S6, and S7). Next, the controller 20 calculates a travel direction of front end of the tractor T at a voluntary point (step 8). Due to this calculated result, controller 20 outputs control signals to the rear wheel hydraulic cylinder 5 and trailer wheel hydraulic cylinder 12, and then, controlling procedure returns to step S1.
Hereinafter, a calculation mode is explained in reference to FIG. 5.
In FIG. 5, symbols A, B, C, and P denote a point of the front end of the tractor T, coupling point, point of the rear end of trailer R, and a center of gravity of wheel base L of tractor T, respectively. Also, symbols δf, δr, and δt denote steering angles of the front wheel 1, rear wheel 4, and trailer wheel 11, respectively. Additionally, all of the angles are represented by radian.
Angle of sideslip βA at point A is:
βA={(B+Lf)/L{δf+{(A-Lf)/L}δr
Angle of sideslip βB at coupling point B is: ##EQU1##
In this equation, Sh(i) corresponds to a direction in which the coupling point B should be advanced.
Hence, a rear wheel steering angle δr, with which angle the coupling point B may advance in the direction of Sh(i), is:
δr={L/(A+H)}{Sh(i)-ψ.sub.1 }-{(B-H)/(A+H)}δf
Angle of sideslip βB1 of coupling point B, which angle βB1 is viewed from trailer R, is:
βB.sub.1 =Sh(i)-ψ.sub.2
A sideslip angle βC of point C on the rear end is:
βC=Sh(1)-ψ.sub.2
In this equation, Sh(1) corresponds to a direction in which point C should be advanced.
Also,
βC={(L1-LR)/L1}βB.sub.1 +(LR/L1)δt
Hence, a trailer wheel steering angle δt, with which the point C can advance in the direction of the yawing angle Sh(1) is:
δt=(L1/LR){Sh(1)-ψ.sub.2 }-{(L1-LR)/LR}{Sh(i)-ψ.sub.2 }
Yawing rate ψ1 of tractor T is:
ψ.sub.1 =(ΔD/L)(δf-δr)
Vehicle angle in a unit time, that is, yawing angle ψ1 is:
ψ.sub.1 =ψ.sub.1 +ψ.sub.1
Yawing rate ψ2 of trailer R is:
ψ.sub.2 =(ΔD/L)(βB.sub.1 -δt)
Yawing angle ψ2 is:
ψ.sub.2 =ψ.sub.2 +ψ.sub.2
Also, assuming that coupling angle=φ, we get:
ψ.sub.2 =ψ.sub.1 -φ
As above-mentioned, the controller calculates Sh(n), which represents a travel direction of point A, due to the front wheel steering angle δf, and memorizes Sh(n) in RAM 23. Also, the controller calculates the rear wheel steering angle δr so that the coupling point B may advance in the same direction, that is, the travel direction on the front end of the tractor when point B reaches a location of the point A. And then, the controller controls the rear wheel hydraulic actuator 5.
Additionally, the controller calculates the trailer wheel steering angle so that point C may advance in the same direction, that is, the travel direction on the front end of the tractor when point C reaches a location of the point A. And then, the controller controls trailer wheel hydraulic actuator 12.
Thus, a path of voluntary point A on the front end of the tractor, coupling point B, and point C on the rear end of the trailer will surely concur (align) with one another.
The second embodiment of the present invention is explained with reference to FIGS. 6-11.
In FIG. 6, a tractor 101 is provided with a steering 111 and link mechanism 113 for steering a pair of front wheels 112 in combination with the steering 111. Also, the tractor 101 is provided with a front wheel steering angle sensor 114 for detecting a steered angle of front wheel 112 by measuring an angle of steering 111, and a coupling angle sensor 117 which is attached to a coupler 116 and detects a coupling angle of the coupler 116. And a numeral 118 denotes a pair of rear wheel of the tractor 101.
On the other hand, the trailer 102 is provided with a vehicle speed sensor 115 for outputting a pulse signal, a frequency of which signal is proportional to a number of revolutions of the rear wheel, link mechanism 122 for steering the rear wheel 121, and a hydraulic actuator 123 for driving the link mechanism 122. Through a servo valve 126, the actuator 123 is connected with an oil pump 124 and an oil tank 125. These members 122-126 construct the steering mechanism. Also, the trailer 102 is provided with a rear wheel steering angle sensor 127 for detecting a steering angle of rear wheel 121. These members, 114, 115, 117, 126 and 127 are connected with a controller, respectively. The controller is represented by a numeral 131, in general.
The controller 131 consists of a microcomputer. A CPU 134 in the controller 131 is connected with a A/D converter 132, which is connected with the front wheel steering angle sensor 114 and the coupling angle sensor 117, and a pulse input interface 133 which is connected with vehicle speed sensor 115. Also, ROM 136 and RAM 137 are connected with the CPU 134, respectively. Through a D/A converter 138 and a servo amplifier 135, the CPU 134 is connected with the servo valve 126, and the servo amplifier 135 is connected with the rear wheel steering angle sensor 127.
Next, a calculation mode is explained in FIG. 7.
In FIG. 7, assume that:
H: center of coupling point, that is, center of the coupler 116;
φ: coupling angle;
C: rear end of the trailer 102;
C.G.: center of gravity of the trailer 102.
Then, a yawing rate ψ1 is:
ψ.sub.1 =(φ-δt)V/Lt                          (1)
A sideslip angle β1 of center of gravity C.G. is:
β.sub.1 =(Ltr·φ/Lt)+(Lft·δt/Lt)(2)
A sideslip angle βc of point C is:
βc=β.sub.1 -(Lc·ψ.sub.1 /V)         (3)
From equations (1) and (2), equation (3) is:
βc={(Ltr-Lc)φ/Lt}+{(Ltf+Lc)δt/Lt}
Assuming that a character Lh denotes a distance between the rear wheel set of tractor 101 and the coupling point H, a sideslip angle βh being viewed from the coupling point, that is, point H, is:
βh=(Lh/L)·df+φ
in which, a character L denotes a wheel base of the tractor 101. Since the distance Lh is so small as compared with the wheel base L, a value of "Lh/L" can be neglected, and therefore, we get:
βh≈φ                                      (4)
A travel direction γh of point H is:
γh=φ+ψ.sub.1                                 (5)
Travel direction γc of point C is: ##EQU2##
If a discretion by a unit travel distance Δx (FIG. 8) is carried out in order to make the point C follow and/or trace a path of the point H,
γc(x)=γh(x-n·Δx)                (7)
in which,
n=(Ltf+Lc)/Δx                                        (8)
From the equations (5) and (6), we get:
{(Ltr-Lc)φ(x)/Lt}+{(Ltf+Lc)δt(x)/Lt}+ψ.sub.1 (x)=γh(x-n·Δx)                       (9)
A yawing angle ψ1 (x) is represented as follows:
ψ.sub.1 (x)=ψ.sub.1 (x-n·Δx)+{(φ(x)+δt(x)Δx/Lt}(10)
The equation (9) may also be transformed as follows:
δt(x)=γh(x-n·Δx)-{(Ltr-Lc)φ(x)/(Ltf+Lc)}-Lt.multidot.φ(x)/(Ltf+Lc)                                 (11)
Thus, the controller operates and/or calculates a travel direction of the point H with every unit travel distance Δx by the equation (5), and memorizes the travel direction in RAM 137. And then, the controller controls a target steering angle of rear wheel 121 of the trailer 102 by the equation (11), so as to make the point C move and/or pass in the same travel direction with the travel direction of the point H memorized in RAM 137 when the point C comes to a location that the point H has already passed.
Next, control modes are explained with reference to FIGS. 9-11.
In FIG. 9, with a key switch (not shown) ON, the controller 131 resets the previously memorized yawing angle ψ1 to zero (step S1), and then, sets a counter of unit travel distance Δx to 1 (step S2). Next, the controller sets the travel direction γh(i) to zero (step S3), and increases a value of the count by one (step S4). Then, when the value of the count reaches a predetermined count n (step S5 is YES), the controller returns. In other words, while the power is ON, a target travel direction of the point C is kept in initialized condition that the point C moves in a straight advance direction until the point C reaches a location where the point H has passed.
In FIG. 10, with every unit time Δt, due to signals generated from the coupling angle sensor 117, the controller 131 detects the coupling angle φ (step S10), eliminates noises (step S11), stores the coupling angle in RAM 137 (step S12), and returns.
In FIG. 11, with every travel distance Δx, the controller 131 reads the coupling angle φ, the yawing angle ψ, the travel direction γh(1) of the point H at the time that the point H was at the present location of the point C, and items (weight and lengths Lc, Lfr, Ltf, Lt, etc.) of the trailer 102 (steps S20, S21, S22, and S23).
Then, the controller 131 calculates the target steering angle δt of the rear wheel 121 with reference to the equation (11) (step S24), and sets the count to 1 (step S25). Then, controller 131 increases the data value of the travel direction γh(i) by one (step S26), increases count value by one (step S27), and determines whether the count value has reached a predetermined count (value) n (step S28).
If No, the controller 131 returns to step S26.
If Yes, the controller 131 calculates a travel direction of the point II by the equation (5) (step S29), stores such the direction in RAM 137 (step S30). Then, the controller 131 calculates the yawing rate ψ1 by the equation (1) (step S31), calculates the yawing angle ψ1 (x) by the equation (10) (step S32), outputs a signal of the target steering angle δt to the servo amplifier 135 (step S32), and then, returns.
Effect of the Invention
The present invention, constructed as explained above, is able to control steering angles of rear wheel and trailer wheels by a feed forward control, make paths of any point on the front end of tractor, coupling point, and a point on the rear end of trailer concur (align) with one another, reduce inner wheel difference of the trailer, make a turn without overhang problems, and improve mobility thereof.
Also, since the present invention is constructed as mentioned above, the rear wheel of trailer can be steered with a simple control, and the mobility of the vehicle carring out the present invention is improved.
In addition, restrictions on trailers to be coupled can be removed.

Claims (14)

I claim:
1. A combination vehicle including a tractor and a trailer comprising:
front wheel steering angle detecting means for detecting a front wheel steering angle of the tractor;
coupling angle detecting means for detecting a coupling angle about a coupling point between the tractor and the trailer;
rear wheel steering angle detecting means for detecting a rear wheel steering angle of the tractor;
trailer wheel steering angle detecting means for detecting a trailer wheel steering angle;
actuators for steering the rear wheels of the tractor and the trailer wheels, separately; and
control means for calculating and memorizing a travel direction of a front end of the tractor at a location along a path of travel in response to signals transmitted from each of said detecting means, said control means transmitting output signals to said actuators so as to align travel directions of the coupling point and a rear end of the trailer with the memorized direction of the front end of the tractor when the coupling point and the rear end of the trailer reach said location.
2. A combination vehicle according to claim 1, wherein the control means includes a microcomputer.
3. A combination vehicle according to claim 2, wherein the microcomputer includes a CPU.
4. A combination vehicle according to claim 2, wherein the microcomputer includes a ROM.
5. A combination vehicle according to claim 2, wherein the microcomputer includes a RAM.
6. A combination vehicle according to claim 1, wherein the control means calculates and memorizes the travel direction of the front end of the tractor at plural, discrete locations in response to said signals transmitted from each of the detecting means, and the control means transmits said output signals to the actuators so as to align the travel direction of the coupling point and the rear end of the trailer with the memorized direction of the front end of the tractor when the coupling point and the rear end of the trailer reach each of the discrete locations.
7. A vehicle comprising:
a tractor provided with a steering mechanism and a link mechanism for steering a pair of front wheels;
a steerable trailer attached to the tractor;
front wheel steering angle detecting means for detecting a front wheel steering angle of the tractor;
coupling angle detecting means for detecting a coupling angle about a coupling point between the tractor and the steerable trailer;
rear wheel steering angle detecting means for detecting a rear wheel steering angle of the tractor;
trailer wheel steering angle detecting means for detecting a trailer wheel steering angle;
actuators for steering the rear wheels of the tractor and the trailer wheels, separately; and
control means for calculating and memorizing a travel direction of a front end of the tractor at a location along a path of travel in response to signals transmitted from said detecting means, said control means transmitting output signals to said actuators so as to align travel directions of the coupling point and a rear end of the trailer with the memorized direction of the front end of the tractor when the coupling point and the rear end of the trailer reach said location.
8. A vehicle according to claim 7, wherein a second link mechanism is provided for steering the rear wheels of the tractor.
9. A vehicle according to claim 7, wherein the vehicle further includes a vehicle speed sensor which is connected to the control means to provide signals to the control means.
10. A vehicle according to claim 7, wherein the control means of the vehicle includes a microcomputer.
11. A vehicle according to claim 10, wherein the microcomputer includes a CPU.
12. A vehicle according to claim 10, wherein the microcomputer includes a ROM.
13. A vehicle according to claim 10, wherein the microcomputer includes a RAM.
14. A vehicle according to claim 7, wherein the control means calculates and memorizes the travel direction of the front end of the tractor at plural, discrete locations in response to said signals transmitted from the detecting means, and the control means transmits said output signals to the actuators so as to align the travel direction of the coupling point and the rear end of the trailer with the memorized direction of the front end of the tractor when the coupling point and the rear end of the trailer reach each of the discrete locations.
US08/073,500 1990-09-26 1993-06-09 Steerable trailer and steering apparatus of combination vehicle Expired - Fee Related US5329451A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US08/073,500 US5329451A (en) 1990-09-26 1993-06-09 Steerable trailer and steering apparatus of combination vehicle

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP1990099741U JP2515731Y2 (en) 1990-09-26 1990-09-26 Steerable trailer
JP2-99741 1990-09-26
JP1990107914U JP2542574Y2 (en) 1990-10-17 1990-10-17 Steering device for articulated vehicles
JP2-107914 1990-10-17
US07/764,304 US5289892A (en) 1990-09-26 1991-09-24 Steerable trailer and steering apparatus of combination vehicle
US08/073,500 US5329451A (en) 1990-09-26 1993-06-09 Steerable trailer and steering apparatus of combination vehicle

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US07/764,304 Division US5289892A (en) 1990-09-26 1991-09-24 Steerable trailer and steering apparatus of combination vehicle

Publications (1)

Publication Number Publication Date
US5329451A true US5329451A (en) 1994-07-12

Family

ID=26440852

Family Applications (2)

Application Number Title Priority Date Filing Date
US07/764,304 Expired - Lifetime US5289892A (en) 1990-09-26 1991-09-24 Steerable trailer and steering apparatus of combination vehicle
US08/073,500 Expired - Fee Related US5329451A (en) 1990-09-26 1993-06-09 Steerable trailer and steering apparatus of combination vehicle

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US07/764,304 Expired - Lifetime US5289892A (en) 1990-09-26 1991-09-24 Steerable trailer and steering apparatus of combination vehicle

Country Status (3)

Country Link
US (2) US5289892A (en)
EP (1) EP0484668B1 (en)
DE (1) DE69105460T2 (en)

Cited By (51)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5523947A (en) * 1993-09-24 1996-06-04 Eaton Corporation System and method for estimating trailer length
US5607028A (en) * 1993-11-29 1997-03-04 Braun; Eric E. All-wheel steering system
US5630604A (en) * 1989-04-13 1997-05-20 Ducote; Edgar A. Remotely-steered trailers
US6016885A (en) * 1997-08-22 2000-01-25 Caterpillar Inc. Steering system
US6186266B1 (en) 1998-08-24 2001-02-13 Marchant Waste Managers Steerable tag axle system
DE10031024A1 (en) * 2000-06-26 2002-01-17 Doll Fahrzeugbau Gmbh Combination road train for transporting long or short material has steering device has additional function with which trailer can be steered independently of steering lock
US6341251B1 (en) * 1999-08-31 2002-01-22 Hino Motors, Ltd. Rear wheel steering control system for rear two-axle vehicle
US6405113B1 (en) * 1999-12-03 2002-06-11 Honda Giken Kogyo Kabushiki Kaisha Vehicle behavior control apparatus
US6409199B1 (en) * 2000-12-04 2002-06-25 Joseph James Boyd Rear wheel steering system
US6431576B1 (en) * 1999-04-28 2002-08-13 Deere & Company System for steering towed implement in response to, or independently of, steering of towing vehicle
US6450523B1 (en) * 1999-11-23 2002-09-17 Nathan E. Masters Steering method for a trailing section of an articulated vehicle
US6494476B2 (en) 2000-05-16 2002-12-17 Nathan Eugene Masters Robotic vehicle that tracks the path of a lead vehicle
US20030167107A1 (en) * 2002-01-10 2003-09-04 Kuhn-Nodet S.A. Method for placing the wheels of a trailer in the wheel tracks left by a tractor vehicle, and device for implementing this method
EP1449745A1 (en) 2003-02-20 2004-08-25 Optima Concept S.a.r.l Method and device for steering a trailer and vehicle with such a device
US20040217575A1 (en) * 2003-05-01 2004-11-04 Pat Beaujot Steering device for towed implements
US20050209763A1 (en) * 2004-03-18 2005-09-22 Ford Global Technologies, Llc Method and apparatus for controlling brake-steer in an automotive vehicle in reverse
US20050206233A1 (en) * 2004-03-18 2005-09-22 Ford Global Technologies, Llc Method and apparatus for maintaining a trailer in a straight position relative to the vehicle
US20050206231A1 (en) * 2004-03-18 2005-09-22 Ford Global Technologies, Llc Method and apparatus for controlling an automotive vehicle using brake-steer and normal load adjustment
US20050206225A1 (en) * 2004-03-18 2005-09-22 Ford Global Technologies, Llc Method and apparatus for predicting the position of a trailer relative to a vehicle
US20050236896A1 (en) * 2004-03-18 2005-10-27 Ford Global Technologies, Llc Method and apparatus of controlling an automotive vehicle using brake-steer as a function of steering wheel torque
US20060076828A1 (en) * 2004-03-18 2006-04-13 Ford Global Technologies, Llc Utility vehicle using brake-steer assisted turning
US20070090688A1 (en) * 2004-02-27 2007-04-26 Daimlerchrysler Ag Control system for a vehicle combination
US7225891B2 (en) * 2003-05-19 2007-06-05 Daimlerchrysler Ag Control system for a vehicle
US20070216134A1 (en) * 2006-02-10 2007-09-20 Padula Santo A Trailer steering system for a tractor/trailer combination
GB2411159B (en) * 2004-02-20 2008-02-27 Coldra Engineering Company Ltd Load guidance system
EP1929185A1 (en) * 2005-09-08 2008-06-11 Volvo Lastvagnar AB A method for adapting gear selection in a vehicle
US20080231701A1 (en) * 2007-03-21 2008-09-25 Jeremy John Greenwood Vehicle maneuvering aids
US20090199530A1 (en) * 2008-02-11 2009-08-13 Gordon Lee Salley Articulated Transport Arrangement For Windrower With Cutting Platform
US20090276122A1 (en) * 2007-05-09 2009-11-05 Prairie Machine & Parts Mfg.(1978) Ltd. Steering system and method for train of wheeled vehicles
US20110112721A1 (en) * 2009-11-10 2011-05-12 Guoping Wang Towable Agricultural Implement Having Automatic Steering System
US20110125371A1 (en) * 2009-11-24 2011-05-26 Guoping Wang Auto-Steerable Farming System
EP2243688A3 (en) * 2009-04-20 2011-11-02 CLAAS Selbstfahrende Erntemaschinen GmbH Corrected forced steering for steered trailers or semi-trailers on multiple axle steering agricultural or forestry traction vehicles
US20110315234A1 (en) * 2010-06-29 2011-12-29 Cnh America Llc Fluid control system for steerable agricultural implement
US20120240546A1 (en) * 2009-12-07 2012-09-27 Georg Kormann Tractor Implement Combination
US20130098703A1 (en) * 2011-10-20 2013-04-25 Sabertooth Motorcycles, Llc Motorized three-wheeled vehicle rear steering mechanism
US8469125B2 (en) 2011-03-25 2013-06-25 Honda Motor Co., Ltd. System and method for controlling a trailer connected to a vehicle
US20130187361A1 (en) * 2012-01-25 2013-07-25 Prairie Machine & Parts Mfg. (1978) Ltd. Hitch system for steering vehicle for train
US8505656B1 (en) 2010-02-10 2013-08-13 Jesus Gonzalez Automotive hauling system
US8626390B2 (en) 2011-01-13 2014-01-07 Cnh America Llc Method for speed based control of an implement steering system
US8914198B2 (en) 2011-01-13 2014-12-16 Cnh Industrial Canada, Ltd. Method for controlling an implement steering system for farm implement in transport
WO2015010671A1 (en) * 2013-07-23 2015-01-29 Friedhelm Hilken Trailing axle having forced steering
US9004519B1 (en) 2011-09-28 2015-04-14 Geoffrey S. Beech Tow bar controlled trailer and method
US9114822B2 (en) 2011-01-13 2015-08-25 Cnh Industrial Canada, Ltd. Method for automatic headland turn correction of farm implement steered by implement steering system
TWI513618B (en) * 2013-10-16 2015-12-21 Aleees Eco Ark Co Ltd An active turning system for articulated buses
US9878740B2 (en) 2013-10-16 2018-01-30 Aleees Eco Ark (Cayman) Co. Ltd. Active steering system for articulated bus
US20180043930A1 (en) * 2015-03-04 2018-02-15 Zhengzhou Research Institute Of Mechanical Engineering Vehicle, single-wheelset/double-wheelset trackless train, and tracking and steering control method therefor
US10350954B2 (en) * 2016-02-02 2019-07-16 Premier Coil Solutions, Inc. Transport trailer load balancing suspension and steering systems
US11129331B2 (en) 2019-01-04 2021-09-28 Cnh Industrial America Llc Steering control system for harvester and methods of using the same
US11643139B2 (en) 2017-11-10 2023-05-09 Syn Trac Gmbh Method for steering a vehicle
US11675357B2 (en) 2019-09-18 2023-06-13 Waymo Llc Independently actuated wheel sets for large autonomous self-driving vehicles
WO2023150274A1 (en) * 2022-02-04 2023-08-10 Zimeno, Inc. Dba Monarch Tractor Tight turn wheel locking

Families Citing this family (59)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5579228A (en) * 1991-05-21 1996-11-26 University Of Utah Research Foundation Steering control system for trailers
SE503204C2 (en) * 1993-06-03 1996-04-15 Arne Henriksson Transporttekni Device for arrangements for steering wheels, for example the rear wheel pair of a trailer
US5479999A (en) * 1994-09-19 1996-01-02 Proia; Cataldo Powered, automatic, self-tracking system for the rear axles of trucks, trailers and buses
US5597087A (en) * 1995-07-07 1997-01-28 Vinarsky; Michael A. Sports bottle
GB9722386D0 (en) * 1997-10-24 1997-12-24 Meritor Hvs Limited Trailer steering system
US5960694A (en) * 1998-02-23 1999-10-05 Eaton Corporation Hydrostatic power steering system having reduced wheel slip
WO2002083480A1 (en) * 2001-04-12 2002-10-24 Mtd Products Inc Four-wheel steering system
US6527078B1 (en) 2001-08-03 2003-03-04 Melvin J. Nelson Steering system for rear wheels of a trailer
US7073620B2 (en) 2003-06-06 2006-07-11 Oshkosh Truck Corporation Vehicle steering system having a rear steering control mechanism
WO2006005124A1 (en) * 2004-07-13 2006-01-19 Gene Kostecki Multiaxle vehicle with steerable rear wheels
GB0715142D0 (en) * 2007-08-03 2007-09-12 Cambridge Entpr Ltd Active steering controller
CN102372022B (en) * 2010-08-26 2013-06-05 中联重科股份有限公司 Multi-axle vehicle electro-hydraulic servo steering system, steering control method and multi-axle vehicle
US9248858B2 (en) 2011-04-19 2016-02-02 Ford Global Technologies Trailer backup assist system
US9290203B2 (en) 2011-04-19 2016-03-22 Ford Global Technologies, Llc Trailer length estimation in hitch angle applications
US10196088B2 (en) 2011-04-19 2019-02-05 Ford Global Technologies, Llc Target monitoring system and method
US9937953B2 (en) 2011-04-19 2018-04-10 Ford Global Technologies, Llc Trailer backup offset determination
US9335163B2 (en) 2011-04-19 2016-05-10 Ford Global Technologies, Llc Trailer length estimation in hitch angle applications
US9513103B2 (en) 2011-04-19 2016-12-06 Ford Global Technologies, Llc Hitch angle sensor assembly
US9434414B2 (en) 2011-04-19 2016-09-06 Ford Global Technologies, Llc System and method for determining a hitch angle offset
US9290202B2 (en) 2011-04-19 2016-03-22 Ford Global Technologies, Llc System and method of calibrating a trailer backup assist system
US8905177B2 (en) * 2012-03-27 2014-12-09 Vitaly Grossman Wheeled platform powered by a cargo tracked vehicle and method of propulsion control thereof
DE102012012572A1 (en) 2012-06-25 2014-01-02 Alois Pöttinger Maschinenfabrik Ges.m.b.H. Device for steering an agricultural implement
SE538165C2 (en) * 2012-10-03 2016-03-22 Scania Cv Ab Control system for an articulated vehicle, and a method in an articulation system in an articulated vehicle
CN102935861B (en) * 2012-12-10 2015-04-01 中联重科股份有限公司 Multi-axle vehicle and steering control system and steering control method thereof
DE102013002565B4 (en) * 2013-02-14 2022-12-22 Man Truck & Bus Se Electric hydraulic unit for steering leading and trailing axles
US9517668B2 (en) 2014-07-28 2016-12-13 Ford Global Technologies, Llc Hitch angle warning system and method
US9963004B2 (en) 2014-07-28 2018-05-08 Ford Global Technologies, Llc Trailer sway warning system and method
US9340228B2 (en) 2014-10-13 2016-05-17 Ford Global Technologies, Llc Trailer motion and parameter estimation system
US9315212B1 (en) 2014-10-13 2016-04-19 Ford Global Technologies, Llc Trailer sensor module and associated method of wireless trailer identification and motion estimation
US9533683B2 (en) 2014-12-05 2017-01-03 Ford Global Technologies, Llc Sensor failure mitigation system and mode management
US9607242B2 (en) 2015-01-16 2017-03-28 Ford Global Technologies, Llc Target monitoring system with lens cleaning device
US9522699B2 (en) 2015-02-05 2016-12-20 Ford Global Technologies, Llc Trailer backup assist system with adaptive steering angle limits
US9616923B2 (en) 2015-03-03 2017-04-11 Ford Global Technologies, Llc Topographical integration for trailer backup assist system
US9804022B2 (en) 2015-03-24 2017-10-31 Ford Global Technologies, Llc System and method for hitch angle detection
US10384607B2 (en) 2015-10-19 2019-08-20 Ford Global Technologies, Llc Trailer backup assist system with hitch angle offset estimation
US10611407B2 (en) 2015-10-19 2020-04-07 Ford Global Technologies, Llc Speed control for motor vehicles
US9836060B2 (en) 2015-10-28 2017-12-05 Ford Global Technologies, Llc Trailer backup assist system with target management
US10017115B2 (en) 2015-11-11 2018-07-10 Ford Global Technologies, Llc Trailer monitoring system and method
US10155478B2 (en) 2015-12-17 2018-12-18 Ford Global Technologies, Llc Centerline method for trailer hitch angle detection
US9827818B2 (en) 2015-12-17 2017-11-28 Ford Global Technologies, Llc Multi-stage solution for trailer hitch angle initialization
US9798953B2 (en) 2015-12-17 2017-10-24 Ford Global Technologies, Llc Template matching solution for locating trailer hitch point
US9934572B2 (en) 2015-12-17 2018-04-03 Ford Global Technologies, Llc Drawbar scan solution for locating trailer hitch point
US9610975B1 (en) 2015-12-17 2017-04-04 Ford Global Technologies, Llc Hitch angle detection for trailer backup assist system
US10011228B2 (en) 2015-12-17 2018-07-03 Ford Global Technologies, Llc Hitch angle detection for trailer backup assist system using multiple imaging devices
US9796228B2 (en) 2015-12-17 2017-10-24 Ford Global Technologies, Llc Hitch angle detection for trailer backup assist system
PL3187397T3 (en) * 2015-12-31 2019-05-31 Tirsan Treyler Sanayi Ve Ticaret Anonim Sirketi Automatic alignment system with warning light
US10005492B2 (en) 2016-02-18 2018-06-26 Ford Global Technologies, Llc Trailer length and hitch angle bias estimation
US10106193B2 (en) 2016-07-01 2018-10-23 Ford Global Technologies, Llc Enhanced yaw rate trailer angle detection initialization
US10046800B2 (en) 2016-08-10 2018-08-14 Ford Global Technologies, Llc Trailer wheel targetless trailer angle detection
US10222804B2 (en) 2016-10-21 2019-03-05 Ford Global Technologies, Llc Inertial reference for TBA speed limiting
EP3652043B8 (en) * 2017-07-13 2021-08-04 Rolf Dr. Meissner Method for maintaining the track of a two-track vehicle
US10710585B2 (en) 2017-09-01 2020-07-14 Ford Global Technologies, Llc Trailer backup assist system with predictive hitch angle functionality
CN108609047A (en) * 2018-03-06 2018-10-02 深圳智慧车联科技有限公司 Vehicle all-wheel control system, method and vehicle
DE112019005571B4 (en) 2018-11-07 2024-04-18 Hitachi Astemo, Ltd. Steering control device, steering control method and steering control system
US11077795B2 (en) 2018-11-26 2021-08-03 Ford Global Technologies, Llc Trailer angle detection using end-to-end learning
US10829046B2 (en) 2019-03-06 2020-11-10 Ford Global Technologies, Llc Trailer angle detection using end-to-end learning
AT524355B1 (en) * 2021-03-04 2022-05-15 Ceres Gmbh System for steering a trailer attached to a towing vehicle
CA3178011A1 (en) 2022-03-11 2023-09-11 Gerard Noel Vehicle steering wheels system
EP4446201A1 (en) * 2023-04-11 2024-10-16 Etablissements Deves Self-steering self-steering axle trailer with autonomous steering

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56163968A (en) * 1980-05-19 1981-12-16 Hino Motors Ltd Automatic followup steering device for trailer
US4553390A (en) * 1981-07-03 1985-11-19 Zahnradfabrik Friedrichshafen, Ag. Hydrostatic steering arrangement
US4565257A (en) * 1984-02-08 1986-01-21 J. I. Case Company Multi-mode steering system
US4570965A (en) * 1982-02-10 1986-02-18 National Research Development Corporation Vehicle steering mechanisms
JPS6160379A (en) * 1984-09-03 1986-03-28 Tokyu Car Corp Steering device for full trailer
US4763916A (en) * 1984-02-24 1988-08-16 Autoipari Kutato Es Fejleszto Vallalat Hydraulic jackknifing-affecting apparatus for articulated vehicles
US4798256A (en) * 1986-11-08 1989-01-17 Zahnradfabrik Friedrichshafen, Ag. Hydrostatic auxiliary steering device
US4848499A (en) * 1985-09-30 1989-07-18 Simon Martinet Servo-control device for steering an articulated vehicle
JPH02120202A (en) * 1988-06-20 1990-05-08 Texaco Dev Corp Preparation of gas mixture containing h2 and co by partial oxidation of chare stock
US5244226A (en) * 1991-09-23 1993-09-14 Bergh C John Trailer and steerable wheels therefor

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS626869A (en) * 1985-07-02 1987-01-13 Nissan Motor Co Ltd Vehicle rear wheel steering device
DE8616691U1 (en) * 1986-06-23 1986-08-07 Doll-Fahrzeugbau GmbH, 7603 Oppenau Log transporter
FR2611635B1 (en) * 1987-02-27 1991-03-15 Billig Sarl Ets CONTROL DEVICE FOR STEERING WHEELS OF A TRAILER, AND TRAILER EQUIPPED WITH SUCH A DEVICE
JPH078652B2 (en) * 1987-09-16 1995-02-01 本田技研工業株式会社 Rear wheel steering angle control method for front and rear wheel steering vehicle
DE3837981C2 (en) * 1988-11-09 1993-10-07 Ernst Winsauer Trucks or semitrailers with a forced steering additional axle

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56163968A (en) * 1980-05-19 1981-12-16 Hino Motors Ltd Automatic followup steering device for trailer
US4553390A (en) * 1981-07-03 1985-11-19 Zahnradfabrik Friedrichshafen, Ag. Hydrostatic steering arrangement
US4570965A (en) * 1982-02-10 1986-02-18 National Research Development Corporation Vehicle steering mechanisms
US4565257A (en) * 1984-02-08 1986-01-21 J. I. Case Company Multi-mode steering system
US4763916A (en) * 1984-02-24 1988-08-16 Autoipari Kutato Es Fejleszto Vallalat Hydraulic jackknifing-affecting apparatus for articulated vehicles
JPS6160379A (en) * 1984-09-03 1986-03-28 Tokyu Car Corp Steering device for full trailer
US4848499A (en) * 1985-09-30 1989-07-18 Simon Martinet Servo-control device for steering an articulated vehicle
US4798256A (en) * 1986-11-08 1989-01-17 Zahnradfabrik Friedrichshafen, Ag. Hydrostatic auxiliary steering device
JPH02120202A (en) * 1988-06-20 1990-05-08 Texaco Dev Corp Preparation of gas mixture containing h2 and co by partial oxidation of chare stock
US5244226A (en) * 1991-09-23 1993-09-14 Bergh C John Trailer and steerable wheels therefor

Cited By (78)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5630604A (en) * 1989-04-13 1997-05-20 Ducote; Edgar A. Remotely-steered trailers
US5523947A (en) * 1993-09-24 1996-06-04 Eaton Corporation System and method for estimating trailer length
US5607028A (en) * 1993-11-29 1997-03-04 Braun; Eric E. All-wheel steering system
US6016885A (en) * 1997-08-22 2000-01-25 Caterpillar Inc. Steering system
US6129170A (en) * 1997-08-22 2000-10-10 Caterpillar Inc. Steering system
US6186266B1 (en) 1998-08-24 2001-02-13 Marchant Waste Managers Steerable tag axle system
US6431576B1 (en) * 1999-04-28 2002-08-13 Deere & Company System for steering towed implement in response to, or independently of, steering of towing vehicle
US6341251B1 (en) * 1999-08-31 2002-01-22 Hino Motors, Ltd. Rear wheel steering control system for rear two-axle vehicle
US6450523B1 (en) * 1999-11-23 2002-09-17 Nathan E. Masters Steering method for a trailing section of an articulated vehicle
US6405113B1 (en) * 1999-12-03 2002-06-11 Honda Giken Kogyo Kabushiki Kaisha Vehicle behavior control apparatus
US6494476B2 (en) 2000-05-16 2002-12-17 Nathan Eugene Masters Robotic vehicle that tracks the path of a lead vehicle
DE10031024A1 (en) * 2000-06-26 2002-01-17 Doll Fahrzeugbau Gmbh Combination road train for transporting long or short material has steering device has additional function with which trailer can be steered independently of steering lock
DE10031024B4 (en) * 2000-06-26 2004-05-19 Doll Fahrzeugbau Gmbh Combination transport train for the transport of long or short material
US6409199B1 (en) * 2000-12-04 2002-06-25 Joseph James Boyd Rear wheel steering system
US20030167107A1 (en) * 2002-01-10 2003-09-04 Kuhn-Nodet S.A. Method for placing the wheels of a trailer in the wheel tracks left by a tractor vehicle, and device for implementing this method
EP1449745A1 (en) 2003-02-20 2004-08-25 Optima Concept S.a.r.l Method and device for steering a trailer and vehicle with such a device
FR2851542A1 (en) * 2003-02-20 2004-08-27 Optima Concept METHOD AND DEVICE FOR GUIDING A TRAILER, VEHICLE EQUIPPED WITH SUCH A DEVICE
US20040217575A1 (en) * 2003-05-01 2004-11-04 Pat Beaujot Steering device for towed implements
US7147241B2 (en) * 2003-05-01 2006-12-12 One Pass Implements Inc. Steering device for towed implements
AU2004201771B2 (en) * 2003-05-01 2011-01-20 One Pass Implements Inc. Steering device for towed implements
US7225891B2 (en) * 2003-05-19 2007-06-05 Daimlerchrysler Ag Control system for a vehicle
GB2411159B (en) * 2004-02-20 2008-02-27 Coldra Engineering Company Ltd Load guidance system
US20070090688A1 (en) * 2004-02-27 2007-04-26 Daimlerchrysler Ag Control system for a vehicle combination
US20050206231A1 (en) * 2004-03-18 2005-09-22 Ford Global Technologies, Llc Method and apparatus for controlling an automotive vehicle using brake-steer and normal load adjustment
US20050206233A1 (en) * 2004-03-18 2005-09-22 Ford Global Technologies, Llc Method and apparatus for maintaining a trailer in a straight position relative to the vehicle
US7165644B2 (en) 2004-03-18 2007-01-23 Ford Global Technologies, Llc Method and apparatus of controlling an automotive vehicle using brake-steer as a function of steering wheel torque
US20050236896A1 (en) * 2004-03-18 2005-10-27 Ford Global Technologies, Llc Method and apparatus of controlling an automotive vehicle using brake-steer as a function of steering wheel torque
US20050206225A1 (en) * 2004-03-18 2005-09-22 Ford Global Technologies, Llc Method and apparatus for predicting the position of a trailer relative to a vehicle
US20060076828A1 (en) * 2004-03-18 2006-04-13 Ford Global Technologies, Llc Utility vehicle using brake-steer assisted turning
US8380416B2 (en) 2004-03-18 2013-02-19 Ford Global Technologies Method and apparatus for controlling brake-steer in an automotive vehicle in reverse
US7950751B2 (en) * 2004-03-18 2011-05-31 Ford Global Technologies Method and apparatus for maintaining a trailer in a straight position relative to the vehicle
US20050209763A1 (en) * 2004-03-18 2005-09-22 Ford Global Technologies, Llc Method and apparatus for controlling brake-steer in an automotive vehicle in reverse
EP1929185A1 (en) * 2005-09-08 2008-06-11 Volvo Lastvagnar AB A method for adapting gear selection in a vehicle
US20090023551A1 (en) * 2005-09-08 2009-01-22 Volvo Lastvagnar Ab Method for adapting gear selection in a vehicle
US8554431B2 (en) 2005-09-08 2013-10-08 Volvo Lastvagnar Ab Method for adapting gear selection in a vehicle
EP1929185A4 (en) * 2005-09-08 2010-08-25 Volvo Lastvagnar Ab A method for adapting gear selection in a vehicle
US20070216134A1 (en) * 2006-02-10 2007-09-20 Padula Santo A Trailer steering system for a tractor/trailer combination
US7793965B2 (en) * 2006-02-10 2010-09-14 Padula Santo A Trailer steering system for a tractor/trailer combination
US9156496B2 (en) 2007-03-21 2015-10-13 Ford Global Technologies, Llc Vehicle maneuvering aids
US9566911B2 (en) 2007-03-21 2017-02-14 Ford Global Technologies, Llc Vehicle trailer angle detection system and method
US9971943B2 (en) 2007-03-21 2018-05-15 Ford Global Technologies, Llc Vehicle trailer angle detection system and method
US20080231701A1 (en) * 2007-03-21 2008-09-25 Jeremy John Greenwood Vehicle maneuvering aids
US7949447B2 (en) 2007-05-09 2011-05-24 Prairie Machine & Parts Mfg. (1978) Ltd. Steering system and method for train of wheeled vehicles
US20090276122A1 (en) * 2007-05-09 2009-11-05 Prairie Machine & Parts Mfg.(1978) Ltd. Steering system and method for train of wheeled vehicles
US8087225B2 (en) * 2008-02-11 2012-01-03 Deere & Company Articulated transport arrangement for windrower with cutting platform
US20090199530A1 (en) * 2008-02-11 2009-08-13 Gordon Lee Salley Articulated Transport Arrangement For Windrower With Cutting Platform
EP2243688A3 (en) * 2009-04-20 2011-11-02 CLAAS Selbstfahrende Erntemaschinen GmbH Corrected forced steering for steered trailers or semi-trailers on multiple axle steering agricultural or forestry traction vehicles
US9849909B2 (en) 2009-11-10 2017-12-26 Cnh Industrial America Llc Towable agricultural implement having automatic steering system
US20110112721A1 (en) * 2009-11-10 2011-05-12 Guoping Wang Towable Agricultural Implement Having Automatic Steering System
US20110125371A1 (en) * 2009-11-24 2011-05-26 Guoping Wang Auto-Steerable Farming System
US9114832B2 (en) 2009-11-24 2015-08-25 Cnh Industrial America Llc Auto-steerable farming system
US20120240546A1 (en) * 2009-12-07 2012-09-27 Georg Kormann Tractor Implement Combination
US8505656B1 (en) 2010-02-10 2013-08-13 Jesus Gonzalez Automotive hauling system
US8640785B2 (en) * 2010-06-29 2014-02-04 Cnh America Llc Fluid control system for steerable agricultural implement
US20110315234A1 (en) * 2010-06-29 2011-12-29 Cnh America Llc Fluid control system for steerable agricultural implement
US9114822B2 (en) 2011-01-13 2015-08-25 Cnh Industrial Canada, Ltd. Method for automatic headland turn correction of farm implement steered by implement steering system
US8626390B2 (en) 2011-01-13 2014-01-07 Cnh America Llc Method for speed based control of an implement steering system
US8914198B2 (en) 2011-01-13 2014-12-16 Cnh Industrial Canada, Ltd. Method for controlling an implement steering system for farm implement in transport
RU2534600C1 (en) * 2011-03-25 2014-11-27 Хонда Мотор Ко., Лтд. System and method for control of vehicle trailer
US8469125B2 (en) 2011-03-25 2013-06-25 Honda Motor Co., Ltd. System and method for controlling a trailer connected to a vehicle
US9004519B1 (en) 2011-09-28 2015-04-14 Geoffrey S. Beech Tow bar controlled trailer and method
US20130098703A1 (en) * 2011-10-20 2013-04-25 Sabertooth Motorcycles, Llc Motorized three-wheeled vehicle rear steering mechanism
US8607913B2 (en) * 2011-10-20 2013-12-17 Ben Daniels Motorized three-wheeled vehicle rear steering mechanism
US8955865B2 (en) * 2012-01-25 2015-02-17 Prairie Machine & Parts Mfg. (1978) Ltd. Hitch system for steering vehicle for train
US9037322B2 (en) 2012-01-25 2015-05-19 Prairie Machine & Parts Mfg. (1978) Ltd. Steering system and method for train vehicle
WO2013110195A1 (en) * 2012-01-25 2013-08-01 Prairie Machine & Parts Mfg. (1978) Ltd. Hitch system for steering vehicle for train
US20130187361A1 (en) * 2012-01-25 2013-07-25 Prairie Machine & Parts Mfg. (1978) Ltd. Hitch system for steering vehicle for train
WO2015010671A1 (en) * 2013-07-23 2015-01-29 Friedhelm Hilken Trailing axle having forced steering
TWI513618B (en) * 2013-10-16 2015-12-21 Aleees Eco Ark Co Ltd An active turning system for articulated buses
US9878740B2 (en) 2013-10-16 2018-01-30 Aleees Eco Ark (Cayman) Co. Ltd. Active steering system for articulated bus
US20180043930A1 (en) * 2015-03-04 2018-02-15 Zhengzhou Research Institute Of Mechanical Engineering Vehicle, single-wheelset/double-wheelset trackless train, and tracking and steering control method therefor
US10647348B2 (en) * 2015-03-04 2020-05-12 Zhengzhou Research Institute Of Mechanical Engineering Co., Ltd Vehicle, single-wheelset/double-wheelset trackless train, and tracking and steering control method therefor
US10350954B2 (en) * 2016-02-02 2019-07-16 Premier Coil Solutions, Inc. Transport trailer load balancing suspension and steering systems
US11643139B2 (en) 2017-11-10 2023-05-09 Syn Trac Gmbh Method for steering a vehicle
US11129331B2 (en) 2019-01-04 2021-09-28 Cnh Industrial America Llc Steering control system for harvester and methods of using the same
US11675357B2 (en) 2019-09-18 2023-06-13 Waymo Llc Independently actuated wheel sets for large autonomous self-driving vehicles
US12085943B2 (en) 2019-09-18 2024-09-10 Waymo Llc Independently actuated wheel sets for large autonomous self-driving vehicles
WO2023150274A1 (en) * 2022-02-04 2023-08-10 Zimeno, Inc. Dba Monarch Tractor Tight turn wheel locking

Also Published As

Publication number Publication date
US5289892A (en) 1994-03-01
DE69105460D1 (en) 1995-01-12
EP0484668A1 (en) 1992-05-13
DE69105460T2 (en) 1995-05-18
EP0484668B1 (en) 1994-11-30

Similar Documents

Publication Publication Date Title
US5329451A (en) Steerable trailer and steering apparatus of combination vehicle
US5523947A (en) System and method for estimating trailer length
JP3928628B2 (en) Vehicle control system
US8548683B2 (en) Active steering controller
US6655710B2 (en) System for detecting trailer instability
US6999856B2 (en) Trailer tongue length estimation using a trailer yaw rate sensor
US7154385B2 (en) Vehicle-trailer backing up system using active front steer
US20070152424A1 (en) Vehicle-trailer low-speed offtracking control
US8245811B2 (en) Hybrid steering system
JP3363869B2 (en) Measurement and control system and method for controlling the lateral direction of a vehicle running continuously back and forth
GB1426316A (en) Steering control system for a motor vehicle
CA1091792A (en) Combined automatic and manual guidance system
US11155298B2 (en) Modified steering angle at completion of hitch assist operation
US6148951A (en) Reactive steering control system
US4832149A (en) Device for correcting the angle of attitude of an automotive vehicle
US5105899A (en) Rear wheel steering angle control system for vehicles
JP3001926B2 (en) Vehicle steering system
JP2001306146A (en) Method for operating machine on prescribed running route and device executint the method
JP2542575Y2 (en) Steering device for articulated vehicles
JP3507215B2 (en) Power steering device
JP2515731Y2 (en) Steerable trailer
JP2956012B1 (en) Self-driving articulated vehicle
JP2542574Y2 (en) Steering device for articulated vehicles
JP2542876Y2 (en) Steering control device for connected vehicles
JPH0635864Y2 (en) Steering device for articulated vehicles

Legal Events

Date Code Title Description
FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20060712